Date Seed-Based Multi-Modal Particulate Admixture for Moderate to Severe Loss Control

ABSTRACT

A date palm seed lost circulation material (LCM) is provided having a date palm seed admixture of date palm seed particles of various sizes. The date palm seed particles may have a size greater than about 2380 microns in a range of about 40% to about 42% by weight, particles having a size greater than about 595 microns and less than about 2381 microns in a range of about 46% to about 48% by weight, particles having a size greater than about 400 microns and less than about 596 microns in a range of about 4% to about 6% by weight, particles having a size less than about 210 microns in a range of about 4% to about 6% by weight, and particles having a size less than about 149 microns in a range of about 1% to about 3% by weight. Methods of lost circulation control using and manufacture of a date palm seed LCM are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims priority from U.S.Non-provisional application Ser. No. 15/436,134 filed Feb. 17, 2017 andtitled “DATE SEED-BASED MULTI-MODAL PARTICULATE ADMIXTURE FOR MODERATETO SEVERE LOSS CONTROL,” which claims priority from U.S. ProvisionalApplication No. 62/361,293 filed Jul. 12, 2016, and titled “DATESEED-BASED MULTI-MODAL PARTICULATE ADMIXTURE FOR MODERATE TO SEVERE LOSSCONTROL,” each of which are incorporated by reference in their entiretyfor purposes of United States patent practice.

BACKGROUND Field of the Disclosure

The present disclosure generally relates to controlling lost circulationin a wellbore during drilling with a drilling fluid. More specifically,embodiments of the disclosure relate to a lost circulation material(LCM).

Description of the Related Art

Lost circulation is one of the frequent challenges encountered duringdrilling operations. Lost circulation, which can be encountered duringany stage of operations, occurs when drilling fluid (or drilling mud)pumped into a well returns partially or does not return to the surface.While some fluid loss is expected, excessive fluid loss is not desirablefrom a safety, an economical, or an environmental point of view. Lostcirculation is associated with problems with well control, boreholeinstability, pipe sticking, unsuccessful production tests, poorhydrocarbon production after well completion, and formation damage dueto plugging of pores and pore throats by mud particles. In extremecases, lost circulation problems may force abandonment of a well.

Lost circulation can occur in various formations, such as naturallyfractured formations, cavernous formations, and high permeableformations. Lost circulation can be categorized by the amount of fluidor mud lost d as seepage type, moderate type, severe type, and totalloss. The extent of the fluid loss and the ability to control the lostcirculation with an LCM depends on the type of formation in which thelost circulation occurs. Formations with low permeability zones, thatis, those with microscopic cracks and fissures, usually have seepagetype lost circulation. Other formations may experience lost circulationif an improper mud weight is used while drilling.

SUMMARY

Lost circulation materials (LCMs) are used to mitigate the lostcirculation by blocking the path of the drilling mud into the formation.The type of LCM used in a loss circulation situation depends on theextent of lost circulation and the type of formation. For example,granular-type LCMs may be used to control lost circulation andstrengthen the near wellbore formation to widen the mud weight window.Such granular-type LCMs may be formed from limestone, marbles, wood,nuts, Formica® corn cobs, and cotton hulls.

Losses of drilling fluids, losses of production, and the costs of LCMs,including importation of LCMs to drilling locations, may result in lostexpenses in drilling operations. Additionally, lost circulation cancause environmental problems if drilling fluids or LCMs interact withthe environment surrounding the reservoir. The manufacture, use, anddisposal of some conventional LCMs may pose a risk to sensitiveenvironments, such as marine environments because they are notbiodegradable and can be toxic to marine life. Additionally, thepurchase and importation of LCMs to drilling locations may be expensiveand time-consuming.

In some embodiments, a method to control lost circulation in a lostcirculation zone in a wellbore is provided. The method includesintroducing an altered drilling fluid into the well bore such that thealtered drilling fluid contacts the lost circulation zone and reduces arate of lost circulation into the lost circulation zone. The altereddrilling fluid includes a drilling fluid and a lost circulation material(LCM). The LCM includes a first plurality of untreated particles havinga first particle size and a second plurality of the untreated particleshaving a second particle size. The untreated particles include grounddate palm seeds. In some embodiments, the method includes adding the LCMto the drilling fluid to create the altered drilling fluid. In someembodiments, the untreated particles consist of ground date palm seeds.In some embodiments, the altered drilling fluid consists of the drillingfluid and the LCM. In some embodiments, the first particle size isgreater than 400 microns and the second particle size is less than 210microns. In some embodiments, the LCM includes a third plurality of theuntreated particles having a third particle size, a fourth plurality ofthe untreated particles having a fourth particle size, and a fifthplurality of the untreated particles having a fifth particle size. Insome embodiments, the first particle size is greater than 2380 microns.In some embodiments, the second particle size is greater than 595microns and less than 2381 microns. In some embodiments, the thirdparticle size is greater than 400 microns and less than 596 microns. Insome embodiments, the fourth particle size is less than 210 microns andgreater than 148 microns. In some embodiments, the fifth particle sizeis less than 149 microns. In some embodiments, the LCM consists of thefirst plurality of untreated particles having a first particle size, thesecond plurality of the untreated particles having a second particlesize, the third plurality of the untreated particles having a thirdparticle size, the fourth plurality of the untreated particles having afourth particle size, and the fifth plurality of the untreated particleshaving a fifth particle size. In some embodiments, the reduced rate oflost circulation is less than an LCM formed from tree nuts and, in someembodiments, the LCM formed from tree nuts comprises an LCM formed fromwalnuts.

In some embodiments, a method of forming an altered drilling fluid isprovided. The method includes drying a plurality of date palm seeds andgrinding the plurality of date palm seeds to produce a plurality ofuntreated particles. The method also includes sifting the untreatedparticles into at least two groups of the untreated particles. The atleast two groups include a first group of the untreated particles havinga first particle size, and a second group of the untreated particleshaving a second particle size. The method also includes mixing the firstgroup and the second group into a lost circulation material (LCM)composition. In some embodiments, the method includes blending the LCMcomposition into a drilling fluid to create an altered drilling fluid.In some embodiments, the drilling fluid is a water-based drilling fluid.In some embodiments, the LCM composition consists essentially of theplurality of untreated particles. In some embodiments, the plurality ofuntreated particles are not introduced to an alkali, an acid, ableaching or an oxidation agent before mixing into the LCM composition.In some embodiments, drying the plurality of date palm seeds includesdrying in the sun over a time period in atmospheric conditions. In someembodiments, the first particle size is greater than 400 microns and thesecond particle size is less than 210 microns. In some embodiments, theat least two groups include a third group of the untreated particleshaving a third particle size, a fourth group of the untreated particleshaving a fourth particle size, and a fifth group of the untreatedparticles having a fifth particle size. In some embodiments, the firstparticle size is greater than 2380 microns. In some embodiments, thesecond particle size is greater than 595 microns and less than 2381microns. In some embodiments, the third particle size is greater than400 microns and less than 596 microns. In some embodiments, the fourthparticle size is less than 210 microns and greater than 148 microns. Insome embodiments, the fifth particle size is less than 149 microns. Insome embodiments, the at least two groups consist of the first group ofuntreated particles having a first particle size, the second group ofthe untreated particles having a second particle size, the third groupof the untreated particles having a third particle size, the fourthgroup of the untreated particles having a fourth particle size, and thefifth group of the untreated particles having a fifth particle size.

In some embodiments, an altered drilling fluid is provided. The altereddrilling fluid includes a drilling fluid and a lost circulation material(LCM). The LCM includes a first plurality of untreated particles havinga first particle size and a second plurality of the untreated particleshaving a second particle size. The untreated particles include grounddate palm seeds. In some embodiments, the untreated particles consist ofground date palm seeds. In some embodiments, the first particle size isgreater than 2380 microns and the second particle size is less than 210microns. In some embodiments, the LCM includes a third plurality of theuntreated particles having a third particle size, a fourth plurality ofthe untreated particles having a fourth particle size, and a fifthplurality of the untreated particles having a fifth particle size. Insome embodiments, the first particle size is greater than 2380 microns.In some embodiments, the second particle size is greater than 595microns and less than 2381 microns. In some embodiments, the thirdparticle size is greater than 400 microns and less than 596 microns. Insome embodiments, the fourth particle size is less than 210 microns andgreater than 148 microns. In some embodiments, the fifth particle sizeis less than 149 microns. In some embodiments, the LCM consists of thefirst plurality of untreated particles having a first particle size, thesecond plurality of the untreated particles having a second particlesize, the third plurality of the untreated particles having a thirdparticle size, the fourth plurality of the untreated particles having afourth particle size, and the fifth plurality of the untreated particleshaving a fifth particle size

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of a process for manufacturing and using a datepalm seed LCM in accordance with an example embodiment of thedisclosure.

DETAILED DESCRIPTION

The present disclosure will now be described more fully with referenceto the accompanying drawings, which illustrate embodiments of thedisclosure. This disclosure may, however, be embodied in many differentforms and should not be construed as limited to the illustratedembodiments set forth in the disclosure. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the disclosure to those skilled in the art.

As a wellbore is drilled, a drilling fluid is continuously pumped intothe wellbore to clear and clean the wellbore and the filings. Thedrilling fluid is pumped from a mud pit into the wellbore and returnsagain to the surface. A lost circulation zone is encountered when theflow rate of the drilling fluid that returns to the surface is less thanthe flow rate of the drilling fluid pumped into the wellbore, and it isthis reduction or absence of returning drilling fluid that is referredto as lost circulation.

Embodiments of the disclosure include a date palm seed LCM that includesdate palm seed (also referred to as “date tree seed”) particles tomitigate or prevent such lost circulation in a well, as well as provideseepage control and minimize or prevent fluid loss. The date palm seedLCM includes a date palm seed particle admixture having at least twosizes of date palm seed particles. In some embodiments, the date palmseed admixture includes particles having a size greater than about 2380microns in a range of about 40% to about 42% by weight of the totalweight of the admixture (w/w %), particles having a size greater thanabout 595 microns and less than about 2380 microns in a range of about46% to about 48% by weight of the total weight, particles having a sizegreater than about 400 microns and less than about 595 microns in arange of about 4% to about 6% by weight of the total weight, particleshaving a size less than about 210 microns and greater than about 148microns in a range of about 4% to about 6% by weight of the totalweight, and particles having a size less than about 149 microns in arange of about 1% to about 3% by weight of the total weight of theadmixture.

In some embodiments, the date palm seed LCM may be added directly to adrilling fluid (for example, a drilling mud) as a preventative approachfor loss circulation control. In some embodiments, the date palm seedLCM may be mixed with a carrier fluid and a viscosifier to form ahomogenous suspension or a pill. In some embodiments, the date palm seedLCM may be combined with another LCM and mixed in a carrier fluid and aviscosifier to form a homogenous suspension or a pill. In someembodiments, the date palm seed LCM may be added as a component of aloss control slurry (LCS). In some embodiments, the date palm seed LCMmay be combined with other LCMs to form an LCM blend for different losscontrol applications. Additionally, the LCM may also be added to adrilling fluid system to increase the fracture gradient due to anincrease in load bearing capacity or hoop stress around the wellbore.

In some embodiments, the date palm seed LCM may include untreated datepalm seed particles. As used in the disclosure, the term “untreated” or“without treating” refers to not treated with alkali or acid, notbleached, not chemically altered, not oxidized, and without anyextraction or reaction process other than possibly drying of water. Theterm “untreated” or “without treatments” does not encompass grinding orheating to remove moisture but does encompass chemical or otherprocesses that may change the characteristics or properties of the LCM.In accordance with this definition, an LCM that is treated may behave ina manner different than its original starting material. In suchembodiments, the date palm seed particles may be manufactured withouttreating before, during, or after crushing, grinding, drying, or anyother processing.

The date palm seed LCM described in the disclosure is chemically inert,physically granular, mechanically strong, biodegradable,environmentally-friendly and non-toxic. As described infra, the datepalm seed LCM may have a plugging efficiency comparable to or betterthan conventional tree nut based LCMs such as a walnut LCM and thus mayhave sealing and blocking capacity better than conventional tree nutbased LCMs.

Examples

The following examples are included to demonstrate embodiments of thedisclosure. It should be appreciated by those of skill in the art thatthe techniques and compositions disclosed in the example which followsrepresents techniques and compositions discovered to function well inthe practice of the disclosure, and thus can be considered to constitutemodes for its practice. However, those of skill in the art should, inlight of the present disclosure, appreciate that many changes can bemade in the specific embodiments which are disclosed and still obtain alike or a similar result without departing from the spirit and scope ofthe disclosure.

The following non-limiting examples of a date palm seed LCM wereprepared and evaluated against a walnut LCM. A date palm seed LCM havinga date palm seed admixture of various sizes of date palm seed particleswas prepared according to the techniques described in the disclosure.The composition of the example date palm seed LCM is shown in Table 1,with the amount of each sized particles expressed in a range of weightpercentage of the total weight (w/w %) and an average weight percentageof the total weight. Table 1 also includes the mesh number of the sievesused in preparing the date palm seed LCM:

TABLE 1 Date Palm Seed Admixture Composition Sieve Minimum date palmRange of w/w % Average w/w % Mesh No. seed particle size 40-42% Retained41% Retained 8 2380 46-48% Retained 47% Retained 30 595 4-6% Retained 5%Retained 40 400 4-6% Passed 5% Passed 70 210 1-3% Passed 2% Passed 100149

Plugging efficiency tests were conducted on the date palm seed LCM andwalnut LCM using a 2 mm slotted disc and a Permeability Plugging Tester(also referred to as “PPT” or “Pore Plugging Test” apparatus)manufactured by OFI Testing Equipment, Inc., of Houston, Tex., USA. Theconventional cell of the Permeability Plugging Tester used in theplugging efficiency test may be operated up to 2,000 psi and 500° F. The2 mm slotted metal disc was used as the filter medium of thePermeability Plugging Tester apparatus in the plugging efficiency test.The plugging efficiency test was performed at conditions of about 250°F. and about 1500 psi differential pressure. Four plugging efficiencytests were performed using four different muds.

The date palm seed LCM and walnut LCM were tested using the PermeabilityPlugging Tester apparatus and the following plugging efficiency testprocedure for each plugging efficiency test:

1. Set the temperature controller/thermostat to the testing temperature;

2. Check the condition of the O-rings in the groove at the top of thetest cell of the Permeability Plugging Tester apparatus and in the cellend cap and replace the O-rings if needed;

3. Apply a thin coating of high temperature grease to all the O-rings,including the two O-rings on the piston of the Permeability PluggingTester apparatus;

4. Screw the T-bar of the Permeability Plugging Tester apparatus intothe piston, install into the bottom end of the test cell, position thepiston about 1 inch into the cell bore, and remove the T-bar;

5. Add a volume of hydraulic oil to the test cell using the hydraulichand pump of the Permeability Plugging Tester apparatus;

6. Install all the O-rings and secure the end cap of the cell inposition such that oil flows from the hole in the end cap to ensure noair is trapped;

7. Install the valve stem into the bottom end cap of the cell, tightenthe valve stem, and disconnect from the hydraulic hand pump of thePermeability Plugging Tester apparatus;

8. Place the cell upright on a suitable stand;

9. Pour a test sample of a homogenous mixture of tested mud and the LCMinto the test cell;

10. Install an O-ring into the top of the cell below the 2 mm slotteddisc;

11. Place the 2 mm slotted disc on top of the O-ring;

12. Insert the end cap on the top of the disc, screw down the threadedretaining ring, and fully tighten;

13. Tighten the top stem of the test cell;

14. Place the cell into the heating jacket of the Permeability PluggingTester apparatus;

15. Connect a pressure hose from the hydraulic hand pump to the bottomof the test cell via a quick connector and ensure the bottom stem isclosed;

16. Connect the back pressure hose/sample collector to the top stem ofthe test cell, ensuring that the locking pin is in place, close thepressure relief valve on the side of the hydraulic hand pump, apply thetesting pressure via the back pressure regulator to the top of the testcell, and close the top valve.

17. Place a thermometer into the hole at the top of the test cell. waituntil the testing temperature is reached, and monitor the cell pressurewhile heating and bleed off pressure if necessary by opening thepressure relived valve on the side of the hydraulic hand pump;

18. Once the test sample has reached the testing temperature, pump thehydraulic hand pump until the pump gauge shows the testing pressure plusthe required back pressure;

19. Apply the required back pressure to the top of the cell, open thetop valve, and pump the hydraulic hand pump to reestablish the testingpressure;

20. To determine the spurt volume, collect the fluid from the backpressure collector in a measuring cylinder and record the amount,ensuring that all the fluid has been expelled;

21. Collect the fluid periodically over a 30 minute time period andcheck the back pressure gauge to ensure that the testing pressureremains less than the pressure threshold (about 3000 psi) of thebuilt-in safety disc of the Permeability Plugging Tester apparatus andavoid expulsion of hot hydraulic oil;

22. Record the spurt loss, total leak off, and PPT values over the 30minute time period and record the cake thickness after dismantling thetest cell.

For the first plugging efficiency test, the date palm seed LCM andwalnut LCM were incorporated into a 65 pounds per cubic foot (pcf)bentonite mud. The composition of the 65 pcf bentonite mud with mudcomponents expressed in pounds-per-barrels (lb/bbl or ppb) is shown inTable 2:

TABLE 2 Composition of 65 pcf bentonite mud Mud Component Lb/bbl Water340.67 Bentonite 25.00 Caustic Soda 0.25 Soda Ash 0.25

Table 3 shows the results of the plugging efficiency tests for the datepalm seed LCM at 10 pounds-per-barrel (ppb) and 30 ppb concentrations inthe 65 pcf bentonite mud and the plugging efficiency tests for thewalnut LCM at 10 ppb and 30 ppb concentrations in the 65 pcf bentonitemud, with the spurt loss, fluid loss, total leak off, and PPT valuemeasured in cubic centimeters (cc) and the cake thickness measured inmillimeters (mm):

TABLE 3 Plugging Efficiency Test Results for Date Palm Seed LCM andWalnut LCM in 65 pcf bentonite mud Total Cake PPT Spurt Fluid Leak offThickness Value Mud LCM Concentration loss (cc) loss (cc) (cc) (mm) (cc)65 pcf Date 10 ppb 0 0.2 0.2 N/A 0.4 bentonite palm mud seed LCM 65 pcfWalnut 10 ppb 1.2 133 134.2 N/A 268.4 bentonite LCM mud 65 pcf Date 30ppb 0 0 0 N/A 0 bentonite palm mud seed LCM 65 pcf Walnut 30 ppb 0 0 0N/A 0 bentonite LCM mud

As shown supra, the 10 ppb concentration of the date palm seed LCMstopped the loss of the whole bentonite mud but allowed some losses ofthe fluid phase from the mud. The 30 ppb concentration of the date palmseed LCM stopped the loss of the whole bentonite mud and the loss of thefluid phase from the mud. Accordingly, both the 10 ppb and 30 ppbconcentrations of the date palm seed LCM showed effective sealing andblocking efficiency. In contrast, the walnut LCM at 10 ppb showed poorplugging efficiency (that is, loss of whole mud and fluid phase from themud), as shown by the significant spurt loss and fluid loss.

A second plugging efficiency test was conducted on the date palm seedLCM and walnut LCM using a 2 mm slotted disc and the PermeabilityPlugging Tester apparatus at about 250° F. and about 1500 psidifferential pressure. For the second plugging efficiency test, the datepalm seed LCM and walnut LCM were incorporated into a 73 pcf KCl-polymermud. The 73 pcf KCl-polymer mud includes PAC LV filtrate controladditive manufactured by BRI-CHEM Supply Corporation of Denver, Colo.,USA. The composition of the 73 pcf KCl-polymer mud is shown

TABLE 4 Composition of 73 pcf KCl-polymer mud Mud Component QuantityWater 310.28 cc Caustic Soda 0.25 grams (g) Soda Ash 0.25 g Bentonite5.00 g PAC LV 3.00 g XC Polymer 1.00 g KCl 42.31 g CaCO₃ 46.80 g

Table 5 shows the results of the plugging efficiency tests for the datepalm seed LCM at 10 ppb and 30 ppb concentrations in the 73 pcfKCl-polymer mud and the plugging efficiency tests for the walnut LCM at10 ppb and 30 ppb concentrations in the 73 pcf KCl-polymer mud:

TABLE 5 Plugging Efficiency Test Results for Date Palm Seed LCM andWalnut LCM in 73 pcf KCl-polymer mud Total Cake Spurt Fluid Leak Thick-PPT loss loss off ness Value Mud LCM Concentration (cc) (cc) (cc) (mm)(cc) 73 pcf Date 10 ppb 0 0.2 0.2 N/A 0.4 KCl- palm polymer seed mud LCM73 pcf Walnut 10 ppb 6.8 92 98.8 N/A 197.6 KCl- LCM polymer mud 73 pcfDate 30 ppb 0 0 0 N/A 0 KCl- palm polymer seed mud LCM 73 pcf Walnut 30ppb 0 0 0 N/A 0 KCl- LCM polymer mud

As shown in Table 5, the 10 ppb concentration of the date palm seed LCMstopped the loss of the whole KCl-polymer mud but allowed some losses ofthe fluid phase from the mud, and. the 30 ppb concentration of the datepalm seed LCM stopped the loss of the whole KCl-polymer mud and the lossof the fluid phase from the mud. Both the 10 ppb and 30 ppbconcentrations of the date palm seed LCM showed effective sealing andblocking efficiency in the tested mud. In contrast, the walnut LCM at 10ppb again showed poor plugging efficiency (that is, loss of whole mudand fluid phase from the mud), as shown by the significant spurt lossand fluid loss.

A third plugging efficiency test was conducted on the date palm seed LCMand walnut LCM using a 2 mm slotted disc and the Permeability PluggingTester apparatus at about 250° F. and about 1500 psi differentialpressure. For the third plugging efficiency test, the date palm seed LCMand walnut LCM were incorporated into an 80 pcf NaCl-polymer mud. The 80pcf NaCl-polymer mud includes PAC LV filtrate control additivemanufactured by BRI-CHEM Supply Corporation of Denver, Colo., USA. Thecomposition of the 80 pcf NaCl-polymer mud is shown in Table 6:

TABLE 6 Composition of 80 pcf NaCl-polymer mud Mud Component QuantityWater 304.64 cc Caustic Soda 0.25 g Soda Ash 0.25 g Bentonite 5.00 g PACLV 4.00 g XC Polymer 1.00 g NaCl 76.16 g Barite 57.90 g

Table 7 shows the results of the plugging efficiency tests for the datepalm seed LCM at 10 ppb and 30 ppb concentrations in the 80 pcfNaCl-polymer mud and the plugging efficiency tests for the walnut LCM at10 ppb and 30 ppb concentrations in the 80 pcf NaCl-polymer mud:

TABLE 7 Plugging Efficiency Test Results for Date Palm Seed LCM andWalnut LCM in 80 pcf NaCl-polymer mud Total Cake Spurt Fluid Leak Thick-PPT loss loss off ness Value Mud LCM Concentration (cc) (cc) (cc) (mm)(cc) 80 pcf Date 10 ppb 0 0.2 0.2 N/A 0.4 NaCl- palm polymer seed mudLCM 80 pcf Walnut 10 ppb 0 0 0 N/A 0 NaCl- LCM polymer mud 80 pcf Date30 ppb 0 0 0 N/A 0 NaCl- palm polymer seed mud LCM 80 pcf Walnut 30 ppb0 0 0 N/A 0 NaCl- LCM polymer mud

As shown in Table 7, both the 10 ppb and 30 ppb concentrations of thedate palm seed LCM stopped the loss of the whole NaCl-polymer mud andthe loss of the fluid phase from the mud. Both the 10 ppb and 30 ppbconcentrations of the date palm seed LCM showed effective sealing andblocking efficiency in the tested mud. As also shown in Table 7, the 10ppb and 30 ppb concentrations of the date palm seed LCM had comparableperformance to the walnut LCM in the NaCl-polymer mud.

A fourth plugging efficiency test was conducted on the date palm seedLCM and walnut LCM using a 2 mm slotted disc and the PermeabilityPlugging Tester apparatus at about 250° F. and about 1500 psidifferential pressure. For the third plugging efficiency test, the datepalm seed LCM and walnut LCM were incorporated into a 90 pcfCaCl₂-polymer mud. The 90 pcf CaCl₂-polymer mud includes PAC LV filtratecontrol additive manufactured by BRI-CHEM Supply Corporation of Denver,Colo., USA. The composition of the 90 pcf CaCl₂-polymer mud is shown inTable 8:

TABLE 8 Composition of 90 pcf CaCl₂-polymer Mud Component Quantity Water294.87 cc Bentonite 5.00 g PAC LV 3.00 g XC polymer 1.00 g Cacl₂ 126.37g Lime 0.50 g Barite 74.60 g

Table 9 shows the results of the plugging efficiency tests for the datepalm seed LCM at 10 ppb and 30 ppb concentrations in the 90 pcfCaCl₂-polymer mud and the plugging efficiency tests for the walnut LCMat 10 ppb and 30 ppb concentrations in the 90 pcf CaCl₂-polymer mud:

TABLE 9 Plugging Efficiency Test Results for Date Palm Seed LCM andWalnut LCM in 90 pcf CaCl2-polymer mud Total Cake Spurt Fluid LeakThick- PPT loss loss off ness Value Mud LCM Concentration (cc) (cc) (cc)(mm) (cc) 90 pcf Date 10 ppb 0 0.2 0.2 N/A 0.4 CaCl₂- palm polymer seedmud LCM 90 pcf Walnut 10 ppb 0.1 2.8 2.9 N/A 5.8 CaCl₂- LCM polymer mud90 pcf Date 30 ppb 0 0 0 N/A 0 CaCl₂- palm polymer seed mud LCM 90 pcfWalnut 30 ppb 0 0 0 N/A 0 CaCl₂- LCM polymer mud

As shown in Table 9, both the 10 ppb and 30 ppb concentrations of thedate palm seed LCM stopped the loss of the whole CaCl₂-polymer mud andthe loss of the fluid phase from the 90 pcf CaCl₂-polymer mud. Both the10 ppb and 30 ppb concentrations of the date palm seed LCM showedeffective sealing and blocking efficiency in the tested 90 pcfCaCl₂-polymer mud. As also shown in Table 9, the 10 ppb and 30 ppbconcentrations of the date palm seed LCM had comparable performance tothe walnut LCM in the CaCl₂-polymer mud.

Thus, as shown in Tables 2-9, the date palm seed LCM may achieve no lossof whole mud and, in some concentrations, no losses of the fluid phasefrom the mud. The loss of the fluid phase from the mud may depend on theconcentration of date palm seed LCM. At concentrations of 30 ppm orgreater in the tested muds, the date palm seed LCM achieve no loss ofwhole mud and no losses of the fluid phase from the mud. Atconcentrations of 30 ppm or greater in the tested muds, the date palmseed LCM achieve no loss of whole mud and negligible loses of the fluidphase from the mud. In some embodiments, the concentration of date palmseed LCM may be increased to achieve no loss of whole mud and no lossesof the fluid phase from the mud.

Date Palm Seed LCM Manufacture and Use

In some embodiments, a date palm seed LCM may be composed of date palmseed particles produced from date palm seeds. The date palm seeds may beproduced as a waste by-product from date processing, and the date palmseeds may be obtained from date processing plants to provide sustainablesource of material for the date palm seeds LCM. In some embodiments, theuse of local sources of date palm seeds may reduce the cost of importedLCM products, components, or both. In some embodiments, the date palmseeds may be obtained from the species phoenix dactylifera. It should beappreciated that, in some embodiments, the date palm seeds may beobtained from genetically modified date trees (that is, geneticallymodified organisms (GMOs)). In some embodiments, the date palm seeds maybe prepared by cleaning the caps before use as an LCM, such as byblowing air over the seeds to remove dust, dirt, and other materials.

In some embodiments, the date palm seed LCM may include a date palm seedparticle admixture having at least two sizes of particles. In someembodiments, the date palm seed LCM may include date palm seed particleshaving a size greater than about 2380 microns in a range of about 40% toabout 42% by weight of the total weight, date palm seed particles havinga size greater than about 595 microns and less than about 2380 micronsin a range of about 46% to about 48% by weight of the total weight, datepalm seed particles having a size greater than about 400 microns andless than about 595 microns in a range of about 4% to about 6% by weightof the total weight, date palm seed particles having a size less thanabout 210 microns and greater than about 148 microns in a range of about4% to about 6% by weight of the total weight, and date palm seedparticles having a size less than about 149 microns in a range of about1% to about 3% by weight of the total weight. In some embodiments, thedate palm seed LCM may include a date palm seed particle admixturehaving at least two or more groups of particles having the size rangesdescribed supra: date palm seed particles having a size greater thanabout 2380 microns, date palm seed particles having a size greater thanabout 595 microns and less than about 2380 microns, date palm seedparticles having a size greater than about 400 microns and less thanabout 595 microns, date palm seed particles having a size less thanabout 210 microns and greater than about 148 microns, and date palm seedparticles having a size less than about 149 microns.

In some embodiments, the date palm seeds may include untreated date palmseeds, thus preserving the environmentally-friendly and biodegradableproperties of the manufacturing process, the fibers, and the resultingLCM composition. As used in the disclosure, the term “untreated” or“without treating” refers to not treated with alkali or acid, notbleached, not chemically altered, not oxidized, and without anyextraction or reaction process other than possibly drying of water. Theterm “untreated” or “without treatments” does not encompass grinding orheating to remove moisture but does encompass chemical or otherprocesses that may change the characteristics or properties of thefibers. In such embodiments, the date palm seeds may be manufacturedwithout treating before, during, or after drying or any otherprocessing.

In some embodiments, the date palm seed LCM may be added directly to adrilling fluid, such as a drilling mud, to create an altered drillingfluid having the date fruit cap LCM. For example, in some embodiments,the date palm seed LCM may be added to (for example, blended with) anoil-based drilling mud or a water-based drilling mud. In someembodiments, the date palm seed LCM may be added at the mud pit of a mudsystem. After addition of the date fruit cap LCM to a drilling fluid,the altered drilling fluid may be circulated at a pump rate effective toposition the altered drilling fluid into contact with a lost circulationzone in a wellbore, such that the date fruit cap LCM alters the lostcirculation zone (for example, by entering and blocking porous andpermeable paths, cracks, and fractures in a formation in the lostcirculation zone, such as forming a plug in a fracture).

As noted in the disclosure, the mechanical properties of the date palmseed LCM may prevent degradation of the date palm seed LCM whilecirculating downhole as a fluid loss additive or formation strengtheningmaterial. Moreover, the eco-friendly, non-toxic, and environmentallyfriendly properties of the date palm seed LCM may minimize or preventany environmental impact, any effect on ecosystems, habitats,population, crops, and plants surrounding the drilling site where thedate palm seed LCM is used.

FIG. 1 depicts a process 100 for producing and using a date palm seedLCM in accordance with an example embodiment of the disclosure.Initially, date palm seeds from the date palms of date trees may becollected (block 102). For example, as discussed supra, date palms seedsmay be collected from waste produced from date palm processing, such asby obtaining the waste at date palm processing facilities.

The collected date palm seeds may be dried (block 104). In someembodiments, the date palm seeds may be dried using a sun drying processover a time period in atmospheric conditions. Next, the dried date palmseeds may be ground (block 106) using, for example a suitable grinder,such as an industrial grinder. In some embodiments, the date palm seedsmay be crushed before being ground. For example, in such embodiments,the date palm seeds may be crushed to first size, and the crushed datepalm seeds may be ground to a second size less than the first size.

Next, the date palm seed particles may be sifted using one or moresieves and size-graded after sifting (block 108). After sifting andsize-grading, the suitable amounts of each size range of date palm seedparticles may be collected and placed in a mixing apparatus (block 110),such as a mixing bowl. The date palm seed particles in the mixing bowlmay be mixed at a low shear rate (block 112) to produce a date palm seedadmixture for use as a date palm seed LCM. In some embodiments, the datepalm seed admixture may be packed for transportation and use. Forexample, the date palm seeds may be packed in paper bags or othercontainers. In some embodiments, for example, a suitable amount of datepalm seed admixture may be transported to an oil and gas operations sitefor use as an LCM. In some embodiments, the date palm seed admixture maybe blended with other LCMs to manufacture a “one sack” LCM system. Forexample, the date palm seed admixture may be blended with a flake LCM, afibrous LCM, or other LCMs, to manufacture a “one sack” LCM system.

In some embodiments, the date palm seed LCM may be added directly to adrilling fluid (block 114), such as a drilling mud, to create an altereddrilling fluid having the LCM. For example, in some embodiments, thedate palm seed LCM may be added to (for example, blended with) anoil-based drilling mud or a water-based drilling mud. In someembodiments, the date palm seed LCM may be added at the mud pit of a mudsystem. After addition of the date fruit cap LCM to a drilling fluid,the altered drilling fluid may be circulated at a pump rate effective toposition the drilling fluid into contact with a lost circulation zone ina wellbore, such that the date fruit cap LCM alters the lost circulationzone (for example, by entering and blocking porous and permeable paths,cracks, and fractures in a formation in the lost circulation zone).

In some embodiments, the date palm seed LCM and one or more additionalLCMs may be added to a drilling fluid (block 116), such as a drillingmud, to create an altered drilling fluid having the LCMs. For example,in some embodiments, the date palm seed LCM and one or more additionalLCMs may be added to an oil-based drilling mud or a water-based drillingmud. In other embodiments, the date palm seed LCM may be added to acement slurry for use in a cementing operation.

The biodegradation properties of the date palm seed LCM may enable thedate palm seed LCM to easily degrade and disappear from the environmentover time and minimize or prevent any environmental impact. Further, thenon-toxic properties of the date palm seed LCM may minimize or preventany effect on ecosystems, habitats, population, crops, and plantssurrounding the drilling site where the date palm seed LCM is used.

In some embodiments, the date palm seed LCM may be mixed with a carrierfluid, a viscosifier, or both. In some embodiments, a date palm seed LCMhomogenous suspension or pill may be formed. For example, a specificcarrier fluid, viscosifier, or combination therefor may be selected toform a homogenous suspension or pill having the date palm seed LCM. Insome embodiments, the carrier fluid may be water or an oil-based fluid.In some embodiments, the carrier fluid may be fresh water, sea water,salt water, diesel oil, mineral oil, or synthetic oil. In someembodiments, the viscosifier may be a clay or a polymer. Next, thehomogenous suspension may be added to a drilling fluid and used in themanner similar to the date palm seed LCM described in the disclosure.

Ranges may be expressed in the disclosure as from about one particularvalue, to about another particular value, or both. When such a range isexpressed, it is to be understood that another embodiment is from theone particular value, to the other particular value, or both, along withall combinations within said range.

Further modifications and alternative embodiments of various aspects ofthe disclosure will be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the embodiments described inthe disclosure. It is to be understood that the forms shown anddescribed in the disclosure are to be taken as examples of embodiments.Elements and materials may be substituted for those illustrated anddescribed in the disclosure, parts and processes may be reversed oromitted, and certain features may be utilized independently, all aswould be apparent to one skilled in the art after having the benefit ofthis description. Changes may be made in the elements described in thedisclosure without departing from the spirit and scope of the disclosureas described in the following claims. Headings used in the disclosureare for organizational purposes only and are not meant to be used tolimit the scope of the description.

1. An altered drilling fluid, comprising: a drilling fluid; and a lostcirculation material (LCM), wherein the LCM comprises: a first pluralityof untreated particles having a first particle size; and a secondplurality of the untreated particles having a second particle size,wherein the untreated particles comprise ground date palm seeds.
 2. Thealtered drilling fluid of claim 2, wherein the untreated particlesconsist of ground date palm seeds.
 3. The altered drilling fluid ofclaim 2, wherein the first particle size comprises greater than 2380microns and the second particle size comprises less than 210 microns. 4.The altered drilling fluid of claim 2, wherein the LCM comprises: athird plurality of the untreated particles having a third particle size;a fourth plurality of the untreated particles having a fourth particlesize; and a fifth plurality of the untreated particles having a fifthparticle size.
 5. The altered drilling fluid of claim 4, wherein thefirst particle size comprises greater than 2380 microns.
 6. The altereddrilling fluid of claim 5, wherein the second particle size comprisesgreater than 595 microns and less than 2381 microns.
 7. The altereddrilling fluid of claim 6, wherein the third particle size comprisesgreater than 400 microns and less than 596 microns.
 8. The altereddrilling fluid of claim 7, wherein the fourth particle size comprisesless than 210 microns and greater than 148 microns.
 9. The altereddrilling fluid of claim 8, wherein the fifth particle size comprisesless than 149 microns.
 10. The altered drilling fluid of claim 4,wherein the LCM consists of: the first plurality of untreated particleshaving a first particle size; the second plurality of the untreatedparticles having a second particle size; the third plurality of theuntreated particles having a third particle size; the fourth pluralityof the untreated particles having a fourth particle size; and the fifthplurality of the untreated particles having a fifth particle size. 11.The method of claim 4, wherein the first plurality of particles comprisean amount in the range of 40 weight percentage of the total weight (w/w%) to 42 w/w %; the second plurality of particles comprise an amount inthe range of 46 w/w % to 48 w/w %; the third plurality of particlescomprise an amount in the range of 4 w/w % to 6 w/w %; the fourthplurality of particles comprise an amount in the range of 4 w/w % to 6w/w %; and the fifth plurality of particles comprise an amount in therange of 1 w/w % to 3 w/w %.
 12. The method of claim 1, wherein thedrilling fluid is selected from the group consisting of a bentonite mud,a KCl-polymer mud, a NaCl-polymer mud, and a CaCl₂-polymer mud.